Technical Field
The present disclosure relates to a sterilization method for medical instruments that involves housing a housing container in an autoclave and sterilizing with a high pressure steam, the housing container having a gas permeable and micro-particle impermeable cover sheet thermally bonded and sealed to an opening edge of a container main body housing a medical instrument. The present disclosure also relates to a sterilization control device used in the method.
Background Art
A syringe barrel such as a pre-Tillable syringe, a pre-filled syringe in which the pre-Tillable syringe is filled with drugs such as a medical solution, a medicinal drug such as an infusion solution, a blood bag, and a medical instrument such as a medical device including a catheter need to be in a clean aseptic state until use, and thus, are housed in a resin housing container and sterilized in advance with a process such as a high pressure steam sterilization process in an autoclave. In JP 2009-183768 A, a syringe barrel, attached with a cap for covering a needle at the distal end and housed in a housing container, to be filled with a medical agent is transported to a factory the syringe barrel is filled with the medical agent. JP 2009-183768 describes sealing the opening of the housing container, in which a plurality of empty syringe barrels is housed, by thermally sealing a cover sheet made from a material having gas permeability such as a high density polyethylene unwoven cloth to the opening edge. Sterilization utilizing an autoclave sterilizer is then performed on the housing container.
After removing the cover sheet sealing the opening from the housing container taken out from the autoclave sterilizer in the factory at the transporting destination, each syringe barrel is filled with the medical agent, and a pusher is inserted into each syringe barrel to obtain a pre-filled syringe. The manufactured pre-filled syringe is packaged with a sterilization packaging bag and then transported to a doctor or the like.
The syringe barrel housed in the housing container and sterilized can be transported to the factory at the transporting destination while maintaining such state. The cover sheet sealing the opening of the housing container is thermally bonded to the opening edge of the housing container by way of a heat seal adhesive consisting of thermoplastic resin applied on the back surface thereof so as to be easily removed in the factory at the transporting destination. However, it was revealed that a part of the cover sheet peels from the opening edge of the housing container in the housing container subjected to sterilization with the autoclave sterilizer. The cause was found to be the cover sheet bulging out toward the outer side of the housing container to a projecting state to the extent that the cover sheet is peeled from the opening edge of the housing container during a temperature-increasing step in which the temperature in the autoclave is increased, a sterilizing step, and a cooling step in which the temperature in the autoclave is lowered.